1. Field of the Invention
The present invention relates generally to a method and apparatus to restore grey water, and more particularly to a method and apparatus to restore grey water resulting from a cleaning activity such as laundry or dishwashing using ozone as a cleaning agent in a compact closed loop system that eliminates tank space, and increases ozone concentration for a more efficient system.
2. Description of the Prior Art
There have been a number of attempts to integrate ozone into the process of recovering grey water for reuse in the cleaning cycle. Ozone is a naturally occurring oxygen compound designated as O.sub.3. Typically, ozone is generated when oxygen, O.sub.2, is exposed to ultraviolet light or an electrical charge which breaks it down to individual oxygen molecules. As it is well known, ozone is an unstable, powerfully bleaching, toxic (only at very elevated concentrations) oxidizing agent with a pungent irritating odor used to purify and deodorize air, to sterilize water, and as a bleach. Ozone is also used to control airborne organics, molds, fungus, bacteria, and viruses by chemically reacting with them. This makes ozone useful in health care applications as a disinfectant such as in patient and operating rooms, physical therapy rooms, laundry and disposal rooms, food service industries, hotels, restaurants, livestock industries among others.
Prior art systems typically use large ozone generators that utilize ambient air as a feed gas. These systems typically produce inconsistent amounts of ozone which are dependant upon the humidity, temperature, contamination and oxygen content of the available air source. Because of the abundance of nitrogen in ambient air (approximately 75% vs. 20% for O.sub.2) nitrous oxide is produced during the process which therefore reduces the number of oxygen atoms available to produce ozone. Generating ozone with nitrogen present produces deleterious nitrous oxides, resulting in nitric acid formation often within both the ozone generator and the air stream expelled by the ozone generator. Such nitric acid in the ozone generator can, because of its conductive properties, reduce the dielectric properties and therefore efficiency, and can severely corrode the equipment with a resultant loss of ozone production and often irreversible damage to the equipment.
U.S. Pat. No. 5,097,556, issued Mar. 24, 1992 to Engel et al. discloses a method for washing laundry without hot water and detergent using a closed loop ozonated wash water system wherein wash water maintained in a storage tank is ozonated by an ozone generator prior to use in a washing machine. Engel et al. processes water in large bulky tanks, uses a plurality of pumps, and manufacturers ozone from ordinary air. The present invention is much less complex and more efficient than the process described in Engel et al. in that it processes water in-stream rather than statically in large bulky tanks, uses far fewer pumps, uses a combination of high purity ozone and oxygen in the chemical portion of the process, uses a water conserving filter design to remove solids, utilizes only one small tank for storage of sufficient water for one cycle of washing, and delivers highly ozonated water to all points of use at all times.
The present invention provides an efficient method and apparatus to restore grey water resulting from a cleaning activity such as laundry. The present invention uses ozone in a closed loop system for recycling to preserve water, to reduce system size, and to enhance the efficiency of the cleaning system.